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ihvrrnn STATES PATENT OFFICE.

NATHANIEL (l. MITCHELL, OF PHILADELPHIA, PENNSYLVANIA, ASSIGNOR OF ONE-HALF TO RUDOLPH A. LOEIVENTHAL, OF NE\V YORK, N. Y.

PRODUCTION OF WASTE RUBBER GOODS.

SPECIFICATION forming part of Letters Patent No. 454,442, dated June 16, 1891. Application filed February 9, 1891. Serial No. 380,815. (No specimens.)

To whom it y 0071106171! The operation imparts distinct properties Be it known that I, NATHANIEL G. MITCH- to the product, as hereinafter pointed out. ELL, a citizen of the United States, and a resi The rubber coming from the vulcanizer eondent of Philadelphia, county of Philadelphia, tains various compounds-such as carbonates 5 5 and State of Pennsylvania, have invented a of lime, sulphates, oxide of lead, lamp-black, new and useful Improvement in the Produc- &c.--the last particularly being supposed to tion of aste Rubber Goods, which improveto be so intimately associated with the rubment is fully set forth in the following specifiher as to be inseparable by any known means. cation. It is believed that the combined act-ion of the 0 [O This invention has reference to the produc rolls and water upon the mass, in the pecution from waste rubber goods-such as old liar condition in which it is found after deboots and shoesof a devulcanized rubber vulcanization by means of live steam under product suitable for reuse in the manufacture pressure, has the effect of liberating and reof various articles made wholly or in part of moving some of the lamp-black as well as 65 india-rubber. other associated compounds. This is indi- The invention may be regarded as an imcated by the fact that when the resulting sheet provement upon that described in Letters Patis stretched until quite thin and held to the ent No. 418,0ii granted to me December 2%, light it shows distinctly a brownish color, a 1889, which may be referred to for a descripcharacteristic which distinguishes it clearly 7o tion of the method of reclaiming rubber most from any other reclaimed rubber product with nearly resembling that forming the subject which I am acquainted. of the present application for patent. The This new product possesses tenacity and main feature of the former method was the elasticity in amuch higher degree than other rolling of the devulcanized stock into sheets reclaimed rubber sheets. It is furthermore 2 5 while permeated with a certain quantity of to be distinguished by the appearance of the moisture, the moisture being preferably that edge when out, which exhibits an iridescent residing in the stock after devulcanization surface, retracting the light in various colors, with live steam under pressure. In practicin marked contrast to the dull lusterless suring said method the best result was obtained face of the other hi gh-grade restored rubbers. 8o 0 by rolling the stock until quite dry. The surface of the sheet, while smooth and The present invention is based upon the velvety like that described in the aforesaid discovery that a notable improvement in the patentthat is to say, uniform in texture and quality of the product is effected by keeping free from grit-is not fiat and even, but, on the stock wet with continued showers or the contrary, presents irregular ridges or ribs, 3 5 sprays of liquid, as Water, While applying the which are more marked as the thickness of pressure by which the devulcanized mass is the sheet increases. Of course the sheet havrolled into sheets. The pressure is most coning been formed, as herein described, maybe veniently applied by means of rolls, (though dry-rolled between smooth rollers, thus proother equivalent devices may be used,) and ducing an even. surface, but without affecting o 40 in carrying on the operation the water may the properties of the product. Not only is be applied by means of a perforated pipe arthe new product thus distinguished by pecuranged over the rollers. It is found also that liar physical characteristics, but it is capable there is advantage in using hot water, and I of more general use and is a more valuable therefore utilize the condensations from the product commercially than other products 5 boilers and other apparatus where steam is heretofore made.

employed. The mere washing of the devul- In practicing the invention it is preferred canized rubber is not the only effect of this to roll the stock after removal from the deprocess, although the removal of impurities vulcanizer between rolls set very close toas fast as they are pressed out by the rolls, gether until it begins to assume the sheet I00 50 preventing them from again being squeezed form, and then to set the rolls farther apart,

back into the mass, is an important result. thus producing a sheet of considerable thickness and shortening somewhat the rolling process.

Having now fully described my said invention, What I claim, and desire to secure by Letters Patent, is

1. That improvement in the art of reclaiming rubber which consists in subjecting a batch of rubber stock impregnated with moisture, as specified, to mechanical pressure and keeping it wet by repeated application of liquid during the pressing operation, substantially as described.

2. The described improvement in the art of reclaiming rubber, consisting in rolling or pressing into sheets a batch of devu'lcanized stock impregnated with moisture and keeping the said stock Wet during the rolling or NATHANIEL C. MITCHELL.

WVitnesses:

E. M. MUNDY, ROBERT A. BRoWN. 

